From: Stephen Frost <sfrost@snowman.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: David Steele <david@pgmasters.net>
Cc: Joe Conway <mail@joeconway.com>
Cc: Magnus Hagander <magnus@hagander.net>
Cc: Michael Paquier <michael@paquier.xyz>
Cc: Nico Williams <nico@cryptonector.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Cc: Robbie Harwood <rharwood@redhat.com>
Subject: Re: [PATCH v20] GSSAPI encryption support
Date: Thu, 4 Apr 2019 12:24:52 -0400
Message-ID: <20190404162452.GM6197@tamriel.snowman.net> (raw)
In-Reply-To: <15827.1554394584@sss.pgh.pa.us>
References: <7b7035e0-3691-ca63-0957-25d17dc11514@2ndquadrant.com>
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<5406.1554388830@sss.pgh.pa.us>
<20190404144818.GI6197@tamriel.snowman.net>
<5945.1554389568@sss.pgh.pa.us>
<20190404150054.GJ6197@tamriel.snowman.net>
<7566.1554391003@sss.pgh.pa.us>
<20190404152439.GK6197@tamriel.snowman.net>
<8476.1554391968@sss.pgh.pa.us>
<15827.1554394584@sss.pgh.pa.us>
Greetings,
* Tom Lane (tgl@sss.pgh.pa.us) wrote:
> I wrote:
> > Stephen Frost <sfrost@snowman.net> writes:
> >> So I'm a bit surprised that it's taking 4 minutes for you. I wonder if
> >> there might be an issue related to the KDC wanting to get some amount of
> >> random data and the system you're on isn't producing random bytes very
> >> fast..?
>
> > Not sure. This is my usual development box and it also does mail, DNS,
> > etc for my household, so I'd expect it to have plenty of entropy.
> > But it's running a pretty old kernel, and old Kerberos too, so maybe
> > the explanation is in there somewhere.
>
> Same test on a laptop running Fedora 28 takes a shade under 5 seconds.
> The laptop has a somewhat better geekbench rating than my workstation,
> but certainly not 50x better. And I really doubt it's got more entropy
> sources than the workstation. Gotta be something about the kernel.
>
> Watching the test logs, I see that essentially all the time on the RHEL6
> machine is consumed by the two
>
> # Running: /usr/sbin/kdb5_util create -s -P secret0
>
> steps. Is there a case for merging the two scripts so we only have to
> do that once? Maybe not, if nobody else sees this.
I do think that mergeing them would be a good idea and I can look into
that, though at least locally that step takes less than a second.. I
wonder if you might strace (or whatever is appropriate) that kdb5_util
and see what's taking so long. I seriously doubt it's the actual
kdb5_util code and strongly suspect it's some kernel call.
Thanks!
Stephen
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To: pgsql-hackers@postgresql.org
Cc: sfrost@snowman.net, tgl@sss.pgh.pa.us, peter.eisentraut@2ndquadrant.com, alvherre@2ndquadrant.com, david@pgmasters.net, mail@joeconway.com, magnus@hagander.net, michael@paquier.xyz, nico@cryptonector.com, rharwood@redhat.com
Subject: Re: [PATCH v20] GSSAPI encryption support
In-Reply-To: <20190404162452.GM6197@tamriel.snowman.net>
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